1. Field
Exemplary embodiments of the present invention relate to a touch panel and a manufacturing method of a touch panel.
2. Discussion of the Background
With the development of computer technologies and digital techniques, peripheral assistance devices have also been developed. Users of personal computers, portable data transfer devices, and other personal information processing devices perform text processes and graphics processes by using various input devices, such as a keyboard and a mouse.
Use of computers is expanding day by day due to the rapid growth of an information-oriented society. Currently, however, there is difficulty in realizing efficient user driving of computerized device by only using the keyboard and the mouse as the input devices. Accordingly, the necessity for a device capable of easily inputting information that has a simple and low-error operation has increased.
As a response to this need, an input device has been developed having superior reliability, durability, innovation, design, and processing related techniques. That is, a touch panel has been realized as an input device capable of inputting information such as text and graphics.
The touch panel is used on a display surface of an image display device, such as a flat display device of an electronic notebook, a liquid crystal display (LCD), a plasma display panel (PDP), and electroluminescent (EL) display, or a cathode ray tube (CRT), and is a tool used to select desired information while a user views the image display device.
Touch panels are divided into a resistive type, a capacitive type, an electro-magnetic type, a surface acoustic wave (SAW) type, and an infrared type. The type of touch panel is selected for use in an electronic device by considering signal amplification, a resolution difference, difficulty of design and processing, optical characteristics, electronic characteristics, mechanical characteristics, inner characteristics, input characteristics, durability, and economy. Currently, the capacitive type of touch panel is most widely applied in the field.
In the case of the capacitive type of touch panel, an upper substrate formed with a first transparent electrode and a lower substrate formed with a second transparent electrode are spaced apart from each other with an insulating member not contacting the first transparent electrode and the second transparent electrode therebetween. Further, the upper substrate and the lower substrate include electrode wiring connected to the transparent electrode. The electrode wiring transmits a change of a capacitance generated in the first transparent electrode and the second transparent electrode to a controller as the touchscreen is contacted for input.
Conventionally, the transparent electrode is formed by using ITO (indium tin oxide) or a conductive polymer such as polyethylene dioxythiophene (PEDOT)/polystyrene sulfonate (PSS). In the case of ITO, electrical conductivity is excellent, however, indium as a raw material is an expensive rare earth metal, and exhaustion thereof is predicted in the next 10 years. Thus, soon, supply may be outweighed by demand. The conductive polymer as a material provided to substitute for ITO has excellent flexibility and is easily processed; however, its electrical conductivity is low.
Recently, an attempt has been made to use a graphene as the transparent electrode of the capacitive type touch panel. However, when using the graphene as the transparent electrode, additional process steps involving graphene growth and an electrode forming are needed, such that the manufacturing process is more complicated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.